Ten South, the high-security wing of the Metropolitan Correctional Center, in Lower Manhattan, is, by design, as grim as any corner of hell. A half dozen narrow cells are lined one after the other, the overhead lights glow day and night, and the tiny window in each cell is frosted, allowing only an opaque hint of the world beyond the prison. There’s a slot in the solid cell door, but it’s kept shut most of the time, and so the prisoner’s unvarying horizon stretches as far as the four cinderblock walls. Only small noises intrude: the chatter of guards, the slamming of cell doors, the high-pitched moan of an inmate.

For over a year, stretching from 1990 to 1991, 10 South was the forbidding home of the triumvirate that still ruled the Gambino crime family as they awaited trial—John Gotti, Frank Locascio, and Sammy Gravano. But in the first days of October 1991, a cunning plan began to take shape to covertly transfer Sammy the Bull, in the pre-dawn hours, from his inhospitable cell.

Today, nearly three eventful decades later, what makes this Great Escape more than just a faded episode from yesteryear’s gangland chronicles, but rather relevant and even instructive, is the identity of the man who ultimately had to sign off on the operation: then U.S. Assistant Attorney General for the Criminal Division Robert Mueller. This is, of course, the same hard-driving crime fighter who, as special counsel, is presently leading the federal investigation into alleged collusion between the Trump campaign and Russia. For months, Mueller has been working his way up the Trump food chain, beginning with a guilty plea by campaign adviser George Papadopoulos, and, more recently, a 12-count indictment against former campaign manager Paul Manafort. (Manafort has pleaded not guilty.) On Friday, after meetings to discuss a deal, the president’s former national security adviser, Michael Flynn, walked into a federal courtroom in Washington, D.C., and pleaded guilty in an arrangement that reportedly includes his testimony against more campaign officials, possibly including Trump’s son-in-law, Jared Kushner, and the president himself.

It is, one person close the administration recently observed, a “classic Gambino-style roll-up.” To understand how Mueller might now proceed, to get a sense of the compromises he’d be willing to make to bag the larger prosecutorial targets in his sights, it’s eye-opening to go back to the deal he cut with Sammy the Bull.

Flynn photographed leaving the Courthouse after pleading guilty to ties with Russia on December 1st.

By Aaron P. Bernstein/Bloomberg/Getty Images.

When Gravano sent word from his cell in 10 South that he wanted to meet with the F.B.I., and that, more pointedly, he wanted to speak to them alone, the overwhelming suspicion was that it was more bull from the Bull. Robert Mueller didn’t believe it. And neither did Bruce Mouw, the head of the F.B.I.’s C-16 team that had painstakingly built the case against Gotti and his henchmen. As Mouw told me years ago, when I was writing my book Gangland, both Mueller and he, as well as just about everyone else involved in the case, thought it was a gangster’s scam. Ignore him, was the dismissive consensus. We’d be giving his lawyer—then Ben Brafman, the same canny criminal attorney now shaping Harvey Weinstein’s defense)—ammunition to hurl back at us with incriminating innuendo in the courtroom.

But Mueller had the final say, and he ordered the F.B.I. to arrange the interview—ensuring that it was done as covertly as any mob sit-down. Ten South was, after all, little more than a narrow corridor, a self-contained universe of adjacent cells. Gravano’s was flanked on one side by mob boss John Gotti, and on the other by the Family consigliere, Frankie Loc. If either of them, men who lived by the kill-or-be-killed rules of their ruthless profession, suspected that the Bull was contemplating becoming a rat, the news would swiftly be passed on to the avenging Gambino family foot soldiers. And Sammy would be a marked man.

The shrewd specifics of the plan that ultimately went forward was conceived by Mouw, who had studied strategy at Annapolis in a previous life. On the morning of October 10, 1991, Gravano was escorted from his cell with deliberate pageantry by a phalanx of guards for a scheduled appointment. The ostensible purpose was to conduct a voice-analysis test; the government wanted to be able to distinguish the Bull’s words from the rumble of muttering tough-guy voices on a series of surreptitiously recorded tapes. Gotti and Frankie Loc had each already suffered through similar sessions.

Brafman was at his client’s side throughout the tedious procedure. After the voice test was concluded, Brafman dutifully watched as the F.B.I. agents escorted Gravano to the secure elevator that would take him downstairs, and then the attorney also left. But no sooner had Gravano’s elevator descended to the basement then one of the F.B.I. agents hit the up button—and Sammy was soon back in the conference room. Neither his own attorney nor the wise guys with whom he shared the tenth floor of the M.C.C. had any idea of the momentous meeting that was about to begin.

Once everyone was seated—between the government attorneys and the F.B.I. agents there was, Mouw would say, about a half dozen anxious people in the room—Sammy began without prelude. “I want to switch sides,” he announced flatly.

It is not difficult to imagine the tortured debate within Mueller’s mind as he weighed the decision. He could allow Sammy, a man who had admittedly killed 19 men, to play for Uncle Sam’s team. Or he could go into the Gotti trial knowing that Teflon Don—the swaggering crime boss who had walked away from three prior trials—could once again get away with murder. Pulling him in one direction was a lifetime of rectitude: a lofty moral code passed on by his education at St. Paul’s School, Princeton University, and the Marine Corps. And doubtlessly pulling him in another direction was a fair share of ambition. He’d be the man who brought down John Gotti, and the world would unquestionably be a better place for it.

As Mueller contemplated making his Faustian deal, there is no institutional record that he spoke directly to Gravano. But I did on several occasions. The time that is embedded most vividly in my memory occurred during a meal we shared when he was living under an assumed name in Arizona.

“First time I killed,” Sammy told me between bites of salmon with dill sauce, “before I pulled the trigger, I wondered how I would feel. Taking a life and all that. But I felt nothing afterwards . . . No remorse. Just ice.” He rambled on introspectively for a bit and then abruptly pointed his fork toward an adjacent booth in the restaurant. “See that blonde over there?” he asked.

I nodded and stared at a tanned woman in a low-cut dress.

“See that guy with her?”

I looked at a man in a suit and tie, his mouth wide open as he laughed with apparent delight at something the woman had said.

“I could go over there, pop him in the back of the head, and come back here and finish my salmon. I know it’s supposed to bother me, but it don’t.”

But it was bothering me. Why was Sammy the Bull telling me this?

Then, without any prodding from me, he explained. “I still don’t like being double-crossed. You just should know I could kill you in a second flat. I’m not threatening you. I’m not saying I would if you double-crossed me. I’m just saying I could. You see the difference?”

I definitely did not, and I thought the time had come to make my position clear. “See that waitress?” I ask. Across from us was a diminutive teenager, as small and thin as a gymnast. “I’d be afraid to double-cross her. She could take me.”

With that bit of submission out of the way, our conversation soon found a more fruitful path. But did Robert Mueller ever get a first-hand hint of Sammy the stone-cold killer? The answer to that question remains part of the secret history of the Gotti case. All that is known with certainty is that Mueller agreed to the deal that would make Gravano the government’s star witness, the lynchpin of the federal case. In return, a murderer with 19 notches on his gun would wind up spending not much more time in jail than a deadbeat dad.

It was Mouw who, accompanied by a single other agent, came to escort Gravano from his cell in 10 South and lead him to his shiny new life as a witness for the prosecution, and he deliberately chose a time when he hoped none of the other inmates would notice. But the shuffle of feet, the opening of doors, and even the whispered voices carried through the tunnel-like corridor of the high-security wing. And all at once John Gotti was on his feet, and he let out a piercing wail as he recognized the act of betrayal that was unfolding just outside his cell door. The plaintive scream, Mouw would say, seemed to echo throughout the entire prison, bouncing off the walls and filling every bit of space. It was a sustained and powerful noise. And he imagined he could still hear the Don’s lamentations as he hustled Gravano into the back of the Chevrolet parked on the street 10 floors below.

Gotti’s lawyer labored hard to make something of the fatuous hypocrisy that secured the government’s case. At one point he gestured to where the 12 jurors were seated and proclaimed that there weren’t enough seats to prop up the corpses of all the men that Gravano had killed. It was a nice bit of theatre, but in the end, when the curtain fell, Gotti was—at last!—found guilty.

And Robert Mueller, who would go on to head the F.B.I., had discovered the logic that is the unwritten precept in any treatise on the art of the deal: winning is better than losing. It is ample justification for most any compromise.

Now, as special counsel, he is once again making deals. He is still determined to get his man at all costs. First he flipped Papadopoulos. And then his office met with Robert Kelner, Michael Flynn’s lawyer. Many accusations were swirling around Flynn, including, not least, his alleged role in a complicated plot to kidnap Muslim cleric Fethullah Gulen in return for a $15 million payday (a charge his lawyer has adamantly denied on his client’s behalf). But on Friday the deal was cut: Flynn was charged with one felony count of making a false statement to the F.B.I. regarding his potentially incriminating conversations with the Russian ambassador.

In return for getting off with what amounts to little more than a slap on his bony wrist—the maximum sentence the former general now faces is five years—Flynn will soon have to keep his side of the bargain. Can there be any doubt that the general who had chanted “Lock her up!” at the Republican National Convention has, like Gravano, agreed “to change sides?” Or is there any doubt that Mueller has brought Flynn into his fold because he has his eye fixed, once again, on bigger prey?

Rumors as to who told Flynn to talk to the Russians, and what he was told to say, are already swirling. Multiple reports on Friday fingered Jared Kushner, in what legal experts have suggested could be a violation of the Logan Act—a potentially outdated law, which makes it illegal for a private citizen to undermine U.S. policy in negotiation with a foreign power, but one that Mueller may use nonetheless. It is not difficult to imagine the wail of indignation, a keening and self-righteous outburst that would rival John Gotti’s at his moment of betrayed shock, that might rise out of the Oval Office when Flynn’s testimony finds its target.